adjustable3 blades

[thirteen]

Is there any blades out there that are auto pitch adjusting to maintain certain speeds? It just might not be within reason.  I do not have any wind driven turbines but just a question.

[fungus]

It is possible, google search the board with "pitch control" and you'll find lots of information. It does require quite a lot of machining skills though.

[GeeMac]

Perhaps a look at a airplane's variable pitch prop will give you some ideas.

[thirteen]

I used to work as a helicopter mechanic when I was in the Army and then the National Guard. I just haven't heard of anyone doing it on a wind generator(turbine).  I think that it would require alot of design but an automatic sytem could be of a benefit if you were in a high wind area. The weight would be the biggest problem. Just thinking of odd ideas for a project. MtMnRoy  

[wdyasq]

Jacobs used a pitch control. Someone has done a lot of your research:

http://tinyurl.com/3dapll

Ron

[thirteen]

thanks for info

[thirteen]

thanks alot of information there to read.

[bob golding]

think you have to decide what size turbine you are going for first. the Hugh piggott style furling system seems to work fine up to around 3 or 4 kilowatt. over that variable pitch might be a better option. don't think it would be worth it below that though. i live in a high wind area and haven't had any problems with a 10 foot prop using Hugh's system. i do shut the turbine down in very high winds though. usually they take a few days to build up so by the time they are up in the 60 mph range the batteries are pretty well charged anyway.

cheers and seasons greetings

bob golding

[coldspot]

Some day, I'd like to use this on a large turbine,

I know its got a few issues but with some work it should be able to work again.

 I've got a very small,(6-7") hub type thing that has three arms that all work together with a center disc being turned that might get some effort down the road maybe.This could maybe be servo driven.

[methanolcat]

   This is not my design only something I have found.

   If your a good at fabricating, have the tools and the time this torque sensing pitch controlled hub would be an interesting way to go, although I would redesign it for use with 3 blades and not 2 and ice would be a problem for this design.

   I believe it senses generator load and changes pitch accordingly to meet the needs of the generator.

    Also in my opinion a waste for a smaller turbine, but definitely interesting and one possibility for a larger wind turbine.

[Flux]

The original question was about speed controlled pitch mechanisms and they are used successfully in many forms.

This torque control idea is interesting. I can see some problems that would need sorting out but the idea is on the right lines.

The biggest issue I have with it is that it fails to destruction, if the alternator comes off load it reverts to fine pitch and will speed up on no load probably to destruction.

It would also need a powerful iron cored alternator to be really useful. With the air gap machines they are relying considerably on stall for protection and any device that avoided this stall would burn things out quicker than usual.

As I see it you would need to keep a furling scheme for overload protection and some attempt at overspeed protection. The considerable complexity of the hub and the need for furling makes it less attractive. It would most likely be useful for an induction generator grid tied scheme but you would still need to solve the overspeed issue on no load.

Flux

[methanolcat]

    Hey Flux, and or anyone else

  I thought that you was right as I have been looking at this set-up for a few days now, especially the bottom picture running this through my mind and trying to picture how this would work.

  Up until a few minutes ago I had come to the same conclusion as you, but I think we had both been looking at it wrong (possibly) and it seemed to operate totally opposite than it should or appears.

  Picture this in your mind and let me know if it makes better since as it does to me.  Looking at the bottom pic. unfortunately not having more pictures to go by, in my mind I was putting the generator (induction motor or PM conversion, like you said) on the bottom side of this hub (springs facing on coming wind), reverse it and put the springs side facing the generator.

  Doing that as I see it makes a bit more since, and IF the generator lost it's load the blades would go into stall (if stall would be the correct term there) then making it a "speed controlled pitch mechanism" assuming the generator could overpower the blades and the load remained constant. There may be more than I am seeing here, not sure.

  Does this sound right? or am I in a state of confusion still.

  Again it's not my design and I'm not trying to sell this on anyone but if I can be made to understand it better I think I would like to proceed in building one myself and testing it's design on a large PM generator I am slowly building (15" diameter using 40 2x1x.5 neo's, 20 poles, 30 coils 3 phase).

  Would this design need to be coupled to some sort of variable load through a complex controller for it to work properly?

  The way I see it now, under a high load the blades would pitch flat to the wind when they should be angled, (this is where I am still confused) or would the compression springs take care of that?

  Your thoughts or anyone else's?

        methanolcat